Catheters are used in various different medical procedures and are a common tool in the health care industry. Even though catheters are generally disposable, many catheters contain sophisticated functional devices for use inside the body. These devices include a wide range of sensors, cutting or ablating devices, and the like, and are used for performing various types of diagnostic and therapeutic functions. Catheters are also used to convey fluids into and out of the body.
Since the function performed by a catheter is generally performed at its distal tip, i.e., the tip furthest inside the patient's body and furthest away from the catheter operator, the position of the distal tip, its orientation, or both are often critical to the success of the procedure. Examples of catheter procedures in which improper positioning of the tip can impair the effectiveness of the procedure are as follows:
Cardiovascular procedures, used as an alternative to bypass surgery for the removal of plaque from arteries: the incomplete removal of plaque is partially responsible for restenosis (recurrence of blockages previously treated), which occurs in approximately 25% of cases; PA1 Urological procedures, where catheters are used for the selective removal of prostate cancer, and for the treatment of urinary tract blockages; PA1 Oncological procedures, where catheters are used for the selective removal of malignant tissue, without harming adjacent healthy tissue, and for performing biopsies in a manner which entails a minimum of trauma in the surrounding tissue; PA1 Neurosurgery, where catheters are used for the precise removal of intracranial hematoma; PA1 Radiology, where guided catheters are used to achieve active stabilization within the cardiac chamber for imaging and mapping; and PA1 Internal procedures in general, such as those where guided catheters are used for fluid aspiration to relieve abscesses, or for localized drug delivery. PA1 a sensor which provides data representing one or more motion parameters of the distal tip of the catheter, such as the position, orientation, or velocity of the tip, including related parameters such as distance from the wall of the bodily vessel or acceleration of the tip; PA1 a control system preferably including a microprocessor and a motion control system, the microprocessor receiving the data from the sensor and comparing the data to a target value, such as to determine position error as the difference between the desired (target) and the actual (sensor-detected) position, and the motion control system being a system which keeps the position error to a minimum at all times by providing motion commands for transmission to the distal end of the catheter; and PA1 a drive or directional control system which receives the motion commands from the motion control system and causes the distal tip of the catheter to move in accordance with the commands.
Vascular procedures, used for the removal of plaque or thrombi from peripheral arteries such as the carotid arteries and the arteries in the legs;
Obstetrics/gynecological procedures, where catheters are used for the selective removal of excessive tissue and cyst growth, and for the delivery of site-specific treatments for ovarian cancer;
In procedures involving sensing and diagnosis, an error in the orientation of the catheter may cause a false reading. In procedures involving the delivery of high concentrations of medication to narrowly delineated sites, the effectiveness of the medication and the minimization of side effects can depend on how precisely the delivery site can be targeted. In procedures involving the removal of diseased tissue by cutting or ablation, proper positioning and orientation of the tip are critical in achieving complete removal of the diseased tissue without harm to healthy neighboring tissue.
Since the point of insertion of the catheter into the body is usually a considerable distance from the target site, it is difficult to attain proper positioning of the catheter tip. To address this problem, various remote control mechanisms have been incorporated into catheter designs, but there is much room for improvement, particularly for catheters which contain highly sophisticated and powerful therapeutic devices and whose functions are needed at sites which are particularly difficult to reach. As catheters become more complex, the need for precise directional control increases.
These and other problems are addressed by the present invention.